March 31, 20233 yr Basement build with specialist infilled concrete blocks - 325mm wide, filled with rebar and C35 concrete. Basement is 2/3 in ground, 1/3 above ground. Internal wall and floor has been tanked using KA tanking slurry. No external insulation - this was not possible due to space restrictions. What is suggestion for wall insulation? I was planning to: >> 50mm XPS Foam glued directly to basement walls > 50mm Expanded Polystyrene EPS70 Insulation Board 2400mm x 1200mm (8′ x 4′) | Insulation Wholesale >> 50mm Metal stud in front, attached floor to ceiling > Metal C Stud Partition - 10 Pack | Steel Framing - Fast Build (fastbuildsupplies.co.uk) and MF Ceilings - Suspended Drop Ceiling Systems - Fast Build (fastbuildsupplies.co.uk) >> Metal stud filled with insulation mineral batts (these would fit nice and snug in between the metal studs) >> Vapour Control Layer >> Plasterboard >> Skim Thoughts please?
March 31, 20233 yr Firstly, what will the basement be used for, and will it be heated? 100mm of XPS / mineral wool is not nearly enough, you want a min of 100mm PIR.
March 31, 20233 yr Author The basement will be a living space. Bar, sofa, tv, office. It will be heated. Floor slab has 100mm of rigid insulation. There will be UFH at 150mm spacing with screed. I dont think keeping heat in will be much of a issue, over the winter it was surprisingly not that cold down there. Trying to keep an eye on moisture control.... will have trickle vents in 3 windows, couple of extractor fans and if needed a dehumidifier. Other option I proposed was Metal stud (50mm) installed slightly off the wall - floor to ceiling Metal stud filled with insulation wool bat (50mm) Vapour Control Layer 37.5mm insulated plasterboard (25mm insulation board, 12.5mm plasterboard) Skim I am not sure about using the insulation batts so close to the walls though. Edited March 31, 20233 yr by steveb21
March 31, 20233 yr How large is it ? Just wondering how much space you lose to insulating internally … ( appreciate you have to though ) .
March 31, 20233 yr If this is a new build you will need a lot more wall insulation. Also, the tanking slurry may well not keep it dry and does not seem to be for habitable basement space.
March 31, 20233 yr Author Its been tanked for a while and has been dry. Approx. 6 months. Area size is 9x6m - so just over 50m2.
March 31, 20233 yr 1 hour ago, steveb21 said: specialist infilled concrete blocks What blocks are these? I did a deep basement using special concrete blocks that joggled about for interlock. But we still had to use a very expensive waterproofing layer outside it and under the floor. I'm nervous about yours. Is it fully designed, and can you tell us more? Re insulation, I would be happy with the floor, as the earth will come to some steady temperature, being a long way from cold weather. I think this is undervalued in theoretical calculations. So on the walls I would want PIR for maximum effect. 100mm again perhaps, (still getting some benefit from being away from the weather) then vcl/ stud/ 25mm service void then 1 layer plasterboard. All assuming it stays dry.
March 31, 20233 yr Author Blocks > Stepoc | Structural Products | Anderton Concrete I really dont want to push more than 115mm. "100mm PIR/ vcl/ stud/ 25mm service void then 1 layer plasterboard." Above would take me nearly to just under 200mm. Really do not want to lose that much space. Would 100mm PIR glued against the walls VCL Plasterboard > fixed onto the PIR Skim What the glue hold things up? I am not planning on attaching anything heavy to the walls. I will have to run service/electrical points via cut outs on the PIR. Edited March 31, 20233 yr by steveb21
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